I'm just about to embark on installing the heating system for our house
refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the
airing cupboard to transition from 22mm copper into 15mm plastic and
then bring the pipes through the floor joists without joins to under the
radiators, then come up to the radiator valves in 15mm copper. The
advantage of this approach is an easier installation and fewer
inaccessible joints.

My question is, what joint to use for the bend between the plastic pipe
running horizontally and the 15mm copper radiator tail? There seems to
be a choice between brass compression and using one of the plastic
pushfit bends. I'm worried that the pushfit joints won't be reliable and
we'll end up with leaks into the ceiling after a few years.

What are there pros/cons?

In article , Jim
writes
I'm just about to embark on installing the heating system for our house
refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the
airing cupboard to transition from 22mm copper into 15mm plastic and
then bring the pipes through the floor joists without joins to under the
radiators, then come up to the radiator valves in 15mm copper. The
advantage of this approach is an easier installation and fewer
inaccessible joints.

My question is, what joint to use for the bend between the plastic pipe
running horizontally and the 15mm copper radiator tail? There seems to
be a choice between brass compression and using one of the plastic
pushfit bends. I'm worried that the pushfit joints won't be reliable and
we'll end up with leaks into the ceiling after a few years.

What are there pros/cons?

That sounds like a good way to do it.

My personal choice is to use a joint that is as least as strong as the
strongest item to be jointed, meaning:

solder or brass compression for copper to copper

brass compression for copper to plastic

plastic or brass compression for plastic

I think this makes the joints more likely to survive under abuse which I
view as inevitable at some point in their life and is quite likely for
joints to radiator tails.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

In an earlier contribution to this discussion,
Jim wrote:

I'm just about to embark on installing the heating system for our
house refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the
airing cupboard to transition from 22mm copper into 15mm plastic and
then bring the pipes through the floor joists without joins to under
the radiators, then come up to the radiator valves in 15mm copper. The
advantage of this approach is an easier installation and fewer
inaccessible joints.

My question is, what joint to use for the bend between the plastic
pipe running horizontally and the 15mm copper radiator tail? There
seems to be a choice between brass compression and using one of the
plastic pushfit bends. I'm worried that the pushfit joints won't be
reliable and we'll end up with leaks into the ceiling after a few
years.
What are there pros/cons?

Either will work. Push-fit is easier to do, but compression fittings are
less bulky - and probably cheaper. Push-fit won't leak as such - but you may
get a few molecules coming out over a period of time and causing a bit of
green corrosion on the copper pipe.

My preference would be for compression elbows as long as you can get at them
easily to tighten them properly. Either way, don't forget the inserts in the
plastic pipes.
--
Cheers,
Roger
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fred wrote:
In article , Jim
writes
I'm just about to embark on installing the heating system for our
house refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the
airing cupboard to transition from 22mm copper into 15mm plastic and
then bring the pipes through the floor joists without joins to under
the radiators, then come up to the radiator valves in 15mm copper.
The advantage of this approach is an easier installation and fewer
inaccessible joints.

My question is, what joint to use for the bend between the plastic
pipe running horizontally and the 15mm copper radiator tail? There
seems to be a choice between brass compression and using one of the
plastic pushfit bends. I'm worried that the pushfit joints won't be
reliable and we'll end up with leaks into the ceiling after a few
years. What are there pros/cons?

That sounds like a good way to do it.

My personal choice is to use a joint that is as least as strong as the
strongest item to be jointed, meaning:

solder or brass compression for copper to copper

brass compression for copper to plastic

plastic or brass compression for plastic

I think this makes the joints more likely to survive under abuse
which I view as inevitable at some point in their life and is quite
likely for joints to radiator tails.

Agree with Fred 100%.

As Roger said - don't forget the inserts.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Jan 13, 5:17*pm, Jim wrote:
I'm just about to embark on installing the heating system for our house
refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the
airing cupboard to transition from 22mm copper into 15mm plastic and
then bring the pipes through the floor joists without joins to under the
radiators, then come up to the radiator valves in 15mm copper. The
advantage of this approach is *an easier installation and fewer
inaccessible joints.

My question is, what joint to use for the bend between the plastic pipe
running horizontally and the 15mm copper radiator tail? There seems to
be a choice between brass compression and using one of the plastic
pushfit bends. I'm worried that the pushfit joints won't be reliable and
we'll end up with leaks into the ceiling after a few years.

What are there pros/cons?

I don't disagree with what others have posted, but personally I'd use
(and have used) plastic push-fit elbows, for ease of use. They're so
easy to fit, and in the unlikely event that you had an issue with them
further down the line, just as easy to replace.

Cheers
Richard

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Jim saying something
like:

My question is, what joint to use for the bend between the plastic pipe
running horizontally and the 15mm copper radiator tail?

The neatest push-fits are Tektite, or just use compression elbows.

Roger Mills wrote:
My question is, what joint to use for the bend between the plastic
pipe running horizontally and the 15mm copper radiator tail? There
seems to be a choice between brass compression and using one of the
plastic pushfit bends. I'm worried that the pushfit joints won't be
reliable and we'll end up with leaks into the ceiling after a few
years.
What are there pros/cons?

Either will work. Push-fit is easier to do, but compression fittings are
less bulky - and probably cheaper. Push-fit won't leak as such - but you may
get a few molecules coming out over a period of time and causing a bit of
green corrosion on the copper pipe.

My preference would be for compression elbows as long as you can get at them
easily to tighten them properly. Either way, don't forget the inserts in the
plastic pipes.

Thanks to everyone who answered. I think we'll use the compression
fittings where we can get to them then.